Diminished third chord

1. What is a diminished third chord?
2. Can you have a diminished 3rd?
3. Why are there only 3 diminished chords?

What is a diminished third chord?

In classical music from Western culture, a diminished third ( Play (help·info)) is the musical interval produced by narrowing a minor third by a chromatic semitone.

Can you have a diminished 3rd?

Being diminished, it is considered a dissonant interval. In equal temperament a diminished third is enharmonic with the major second, both having a value of 200 cents. However in meantone tunings with fifths flatter than the 700 cents of equal temperament, the diminished third is wider than the major second.

Why are there only 3 diminished chords?

Because an octave is 12 semitones, stacking further minor 3rd above the top note of a diminished chord just repeats the same existing notes (D → F → A♭ → B → D → F → A♭ → B → D → etc.). ... This means there are only 3 unique diminished chords: Cdim7 = E♭dim7 = G♭dim7 = Adim7.